On-farm crop diversity, conservation, importance and value: a case study of landraces from Western Ghats of Karnataka, India

Landraces are important genetic resources that have a significant role in maintaining the long-term sustainability of traditional agro-ecosystems, food, nutrition, and livelihood security. In an effort to document landraces in the on-farm conservation context, Central Western Ghat region in India was surveyed. A total of 671 landraces belonging to 60 crops were recorded from 24 sites. The custodian farmers were found to conserve a variety of crops including vegetables, cereals and pulses, perennial fruits, spices, tuber and plantation crops. The survey indicated a difference in the prevalence of landraces across the sites. A significant difference with respect to the Shannon-diversity index, Gini-Simpson index, evenness, species richness, and abundance was observed among the different survey sites. Computation of a prevalence index indicated the need for immediate intervention in the form of collecting and ex situ conservation of landraces of some crops as a back-up to on-farm conservation. The study also identified the critical determinants of on-farm conservation, including (i) suitability to regional conditions, (ii) relevance in regional cuisine and local medicinal practices, (iii) cultural and traditional significance, and (iv) economic advantage. The information documented in this study is expected to promote the collection and conservation of landraces ex situ. The National Genebank housed at ICAR-NBPGR, New Delhi conserves around 550 accessions of landraces collected from the Central Western Ghats region surveyed in this report. Information collected from custodian farmers on specific uses will be helpful to enhance the utilization of these accessions.


Methodology Sampling methods and data collection
The survey to document the on-farm conservation was conducted in Central Western Ghats covering four districts viz., Uttara Kannada, Shivamogga, Dakshina Kannada and Belagavi of Karnataka state in the southern part of India (Fig. 1).Initially, basic information regarding the distribution and type of crops, landraces and custodian farmers were collected by communicating with the resource-rich persons, local Krishi Vigyan Kendras (KVKs), agriculture colleges, non-government organizations and Protection of Plant Varieties and Farmers' Rights Authority, (PPV&FRA) New Delhi.
With the gradual replacement of landraces and changes in cropping pattern, there is a significant reduction in the on-farm conservation sites where landraces are cultivated.In such a scenario, where participants are difficult to locate, surveyors have used snowball sampling techniques 21 .We also used this nonprobability technique to identify potential on-farm conservation sites.Snowball sampling or chain referral sampling is a useful tool for analyzing rare instances or in our case, unexposed conservation sites.Resource persons from local KVKs and/ or other organizations provided information about farmers conserving landraces in the respective jurisdiction.www.nature.com/scientificreports/ The survey was conducted from November 2020 to November 2021 to record the landrace diversity of different crops and their status.Based on the initial information obtained, farm households/farmers engaged in landrace conservation or mainly practicing low-input organic agriculture were pooled for information.The data was collected using socio-metric survey with snowball sampling technique 22 where, custodian farmers were identified through data provided by other fellow farmers.A simple questionnaire was used to conduct the survey, which was based on an interview method and field observations.Farmers' fields were visited to record the details of landraces and factors determining their conservation and use.Farmsteads were mapped based on geo-coordinates.Each landrace was recorded with botanical name, common name and the local name.Further, the farmers were also interviewed to obtain personal information, their farm details (landrace cultivation area, total farm area, cropping pattern), cultivation constraints, reasons for not growing landraces, community knowledge of biodiversity conservation and on-farm conservation, present and past use of landraces, traditional and cultural uses associated with the landraces, etc. Efforts were made to document the purpose of cultivating each crop species based on the total economic value (Fig. 2).In the entire exercise, we made sure to comply with relevant institutional, national, and international guidelines and legislations while documenting of on-farm conservation of landraces.

Features of the study area
The Western Ghats Region in Karnataka, locally known as Malenadu lies between 12° 2′ 7″ N and 15° 44′ 46″ N latitude and 74° 14′ 3″ E and 75° 76′ 17″ E longitude.The Central Western Ghats Region extends through an area of 37,000 km 2 covering areas of Chamarajanagara, Mysuru, Kodagu, Dakshina Kannada, Udupi, Hassan, Chikkamagaluru, Shivamogga, Uttara Kannada and Belagavi districts.The climate in the Western Ghats varies with the altitudinal gradation and distance from the Arabian Sea coast.The climate is humid and tropical in the lower reaches tempered by the proximity to the sea.Mean temperatures range from 20 °C (68°F) to 24 °C (75°F).The area is plain and the climate is humid along the west coast; thick forest and hilly area in the center; and tropical monsoon climate with undulated area towards the east side.Agricultural land in this region comprises of a variety of soil types including red soils, laterite soil, black soils and humid soils.Rice, spices, areca nut, jackfruit, cashew nut and sugarcane crops cover majority of the agricultural land area 23,24 .Weather parameters, land utilization and cropping pattern of the surveyed area are given in Table 1.

Statistical analysis
The data on the status of on-farm conservation and management in the region was gathered from multiple survey visits over a period of one-year.The data was analyzed by considering the cultivation of landraces across different districts in order to determine diversity and distribution.The following indices were computed to interpret the collected data: where H = Shannon diversity index; P i = Proportion of individuals of ith species in a whole community 25 .where n = Individuals of a given type/species; N = Total number of individuals in a community.The Gini-Simpson index (or Simpson's index of diversity) measures the probability that the two randomly selected individuals belong to different species 26 .

Total economic value of landraces of different species conserved on-farm
where n i = Number of individuals in the ith species; and N = Total number of individuals in the community.

Informed consent
The authors have obtained the consent from the custodian farmers and they are aware of the intended publication of information and images of the same.

Inventory of landraces and prevalence
Landraces were documented from the Central Western Ghats spanning four districts of Karnataka.Snowball sampling allowed us to reach 24 farmsteads during the study.A total of 671 unique landraces belonging to 60 different crops were documented.These landraces belonged to fruits (8 crops, 181 landraces), vegetables (9 crops, 54 landraces), spices (8 crops, 40 landraces), pulse crops (4 crops, 15 landraces), plantation crops (3 crops, 11 landraces), tuber crops (4 crops, 32 landraces) and few miscellaneous plants (23 crops, 24 landraces).Rice was the only cereal crop documented in the region.However, out of the 671 unique landraces documented, 314 belonged to rice.Rice and fruits together accounted for three fourths of the total landraces documented.
The survey indicated that farmsteads with on-farm conservation and custodian farmers involved in cultivation of landraces were few and far between.It was clearly observed that even farmers immediately neighboring the on-farm farmsteads were not cultivating landraces.If a given landrace is cultivated at more than one on-farm conservation site, there is greater probability of continuity of conservation and availability.In other words, it is important to understand the prevalence of a landrace during the documentation process.
Based on the nomenclature synonymy of landraces, a Prevalence Index (PI) for on-farm conserved landraces was assessed as: Out of 671 landraces documented during the survey, it was found that as many as 243 landraces were cultivated by two or more custodian farmers.It was observed that frequency of occurrence ranged from 1 to 7 (Table 2).The prevalence index was highest for banana (1.95).The PI of rice was 1.53 followed by chili (1.5), jackfruit (1.35), mango (1.33), ridge gourd (1.28), pepper (1.26), lab-lab bean (1.25) and brinjal (1.06) (Table 2).Meanwhile, for remaining 28 crops the value of PI was 1, showing that only one occurrence per landrace was recorded across the survey area.
A solitary farmstead practicing on-farm conservation of local landraces in a given area is matter of pride as well as concern.A family practicing on-farm cultivation of traditional cultivars singlehandedly contributes, as the custodians, towards conservation and perpetuity of landrace diversity.On the other hand, discontinuation of this practice by the custodian family due to any reason could possibly lead to irreversible loss of the landraces.Germplasm explorations by collectors may need to urgently focus on such landraces to ensure that these are conserved ex situ.Stakeholders may also look at promoting seed exchange among the farming community in order to increase their chance of "conservation by use".

Importance of landraces
The landraces across farmsteads were documented to be conserved for their specific uses such as culinary purposes in raw, cooked, pickled and processed form, medicinal value or multiple uses (Table 3).

Fruits
Fruit landraces were found growing on the bunds, near the roadside, on marginal lands, in kitchen gardens and in between plantation crops in the fields mainly for personal use and not as commercial crops.Mango landraces have been conserved for their use in making pickles 27 .One of the unique landraces of mango to this region, Appemidi (used for pickle preparation only) has got Geographical Indication (GI) for Shivamogga and Uttara Kannada region.Neeru Kukku, a special landrace of Dakshina Kannada, can be soaked in salt water for 1-2 years without damaging the quality (named for this quality) and is also used in making huli for sambar (adds aroma and sour taste to sambar instead of tamarind) (Fig. 3a).This area also accommodates huge diversity of jackfruit, kokum and banana landraces than any region, owing for their adaptation and good growing conditions in the region.In jackfruit, soft fruited (Biluva or Ambli types) varieties are used in preparation of local cuisines (idli, kadubu) and hard fruited (bakke type) landraces are used in the production of processed food products such as paapad and chips (matured fruit before ripening); and is also consumed as a fruit.Mankale Red, a landrace of jackfruit from Mankale, a place in Sagara (Shivamogga) has red fruits in which both rags and tendrils have a pleasant flavor when consumed (Fig. 3b).Banana landraces like Elakki Baale, Mitli; pineapple landrace like Ananus Local and jamun landraces are used as dessert fruit; Hoo Baale (flowers), Kadhali/Deva Baale (flowers), Sakkare Baale are used as vegetable (Fig. 3c).Landraces like Betta Baale (pseudo-stem is used for kidney stones) and Kallu Baale (used to treat kidney stones and grows on stones in the hilly regions) have medicinal properties.Meanwhile, some kokum landraces like Uppage Local (making huli for sambar, extract oil from seeds, juice preparation), Muruga Huli and Punarpuli (Fig. 3d) are well-maintained.Vasugi et al. 27 assessed the diversity and morphological variations of Appemidi mango varieties in the same region.In the same way, Pradeep et al. 28 observed cultivation of many landraces (> 20 each) in native crops such as mango and banana in Kerala, which is adjacent to our study area.

Spices
Spices are high-value crops with large-scale export potential 29 .As a result, collecting and preserving spice crop germplasm is critical.In this regard, the Central Western Ghats holds a vast diversity of spice landraces for yield traits, resistance to disease and pests than improved varieties.Karimunda (spicier, good keeping quality i.e., 50-100 years), Vakkalu, Gejje Hipli, Malligesara (good yield potential) (Fig. 4a) and Thekkam Bunch Pepper (Fig. 4b) are few landraces of pepper 30 .Maavina Kaayi Arishina and Kukku Shunti were fragrant type landraces in turmeric and ginger respectively.While Jawari Arishina (turmeric) (Fig. 4c) contains more curcumin (7-8%) content and Jawari Shunti (ginger) is spicier and more pungent than the released varieties as per the farmers' knowledge.Nutmeg used for preparation of ayurvedic formulations.Highly fragrant landrace of clove and some cardamom landraces like Naati Yelakki (Fig. 4d), Kilara, Lambodi Thali and Gundu Kaalu were recorded during the survey.Saji et al. 31 reviewed the conservation aspects and cultivar diversity of different spices of Western Ghats in particular and India in general.

Plantation crops
Plantation crops like areca nut, coffee, coconut and betel vine are the major crops grown in the region, hence their landraces too.Betel wine landraces namely, Kasaravalli, Lakkavalli, Naagavalli and Panchavalli are recorded during the study with limited information of the same regarding their importance and characteristics 31 .Areca nut landraces like Sonda and Dodda Adike are reported from the locality.Tiptur Local is a famous variety of coconut grown all over the Karnataka state.

Vegetables
Though the climate and weather of the Central Western Ghats region restrict the commercial cultivation of vegetables, many farmers grow landraces of different vegetables which are adapted to the locality's soil and climate (Fig. 5).They grow, maintain, promote and preserve these landraces by harvesting the matured fruits for seeds to sow in the next generation.These landraces develop special traits over the years for its climate and soil conditions.Brinjal landrace Udupi Mattu Gulla has very thin skin and small spines on the fruit surface 32  Most of the tuber landraces viz., Bili Genasu, Thuppada Genasu, Kempu Genasu, Nagar Cone and Taambde Cone (yam) are used as vegetable and making sambar.Some tubers like Chirike (highest vitamins) (yam) and Taikilo (taro) (immunity booster and healing of wounds as antiseptic) are also used for their medicinal properties.In a special case of Kunabi tribes in the Joida area of Uttara Kannada, different tuber crops and their wild relatives were documented.Some of the documented landraces are also mentioned by Asha et al. 18 .Similar documentation work in tuber crops was also conducted by Alwis et al. 10 in Sri Lanka.Rice is the staple crop of the region.Despite having many adversaries, many farmers are indulging themselves in cultivating, maintaining, promoting hundreds of rice landraces, which are very well adapted to the region's climate and other agro-ecological factors.Some of the interviewed farmers are preserving hundreds of landraces because of their passion for conservation, market value, and in order to maintain the legacy of their ancestors.Some of the famous landraces maintained even now in the region are Nereguruli Batta (thrives in submergence for 40 days), Rajamudi (high tillering ability, organic cultivation, kernels are red and white rice type with soft rice, good for diabetes and was once patronized by kings of Mysuru Wodeyars), Kayime and Kutti Kayime (red seed kernel, high fodder yield, rabi season variety) and Kempu Hasudi (higher yield; resistant to diseases; red grains with good taste).Puffed rice (Adnen Kelti, Bili Hegge), medicinal value for humans and livestock diseases (Athikaraya, Chitaga), for making sweets (Bile Aloorsanna), for dose and idli (Mallige Sanna), aromatic rice and for making sweet dishes (Gandasaale, Gulvadi Sanna, Indrani, Kaagi Saale), red rice landraces to increase blood hemoglobin (Hasudi, Hejje Batta), can be grown in saline water (Kagga Batta), increases milk in lactating women, good for pregnant, more iron content (Kare Gajuli), good for snacks (Mullare, Bili Halaga), good for diabetes (Rajamudi, Sorata).Importance of rice landrace conservation and their characteristics are also highlighted by Rathi et al. 33 in Chhattisgarh region and by Agnihotri et al. 34 in Kumaon region of Uttarakhand.

Pulses
People consume pulses as their side dish along with staple food.There were six type of pulses were documented during the survey.Only few farmers are growing the pulses though not as main crop but as intercrop or in bunds.Lab-lab bean, a crop mainly grown in southern India, has different morphological variation in each landrace (Chapparada Avare, Matti Avare, Katti Avare, Chaturbuja Avare).Same for Bengal gram (Kempu Kadale, Hasiru Kadale, Kappu Kadale) and cowpea (Kappu Halasande, Kempu Halasande, Bannada Halasande) has variation in colour of the seeds and pods.Immature pods and leaves of some pulses use as vegetable.

Miscellaneous crops
India is known for traditional medicine system since ancient times.Thus, significance of the medicinal plants is known as part of Indian codified medicinal systems like Ayurveda as well as indigenous traditional knowledge about the medicinal uses by the community.In our survey, some plants were recorded for their multipurpose utility including medicine.The people in the region were found to treat various ailments since generations using local plants including Kalmegh (Jeerad Kaddi) for fever, Basella's (Basale Soppu) leaves as coolant, wild purslane

Diversity indices
Based on the landrace nomenclature, Shannon-diversity index (H), Gini-Simpson index (1-D), Evenness (E), Species richness (R), and Abundance (A) were assessed between the crop groups of different districts.Significant differences in these parameters among the four study areas were observed.Shannon diversity index (H) dictates how diverse the species in a given area.Higher the index, more diverse the nature of species in that habitat 35 .Among the study areas, Shannon diversity (H) of Uttara Kannada (H = 2.01) was highest, followed by Shivamogga (H = 1.85),Dakshina Kannada (H = 1.61), and Belagavi (H = 1.3) had limited landrace diversity (Fig. 6).The value of Gini-Simpson's index (1-D) reflects how many different types of species are in a community and how evenly each species is distributed.Similarly, Uttara Kannada showed more diversity in landraces with a Gini-Simpson index value of 0.77 and Belagavi showed very less diversity with a value of 0.56.In terms Gini-Simpson index, Belagavi and Dakshina Kannada exhibited comparable diversity levels with values of 0.56 and 0.59, respectively (Fig. 6).Ocimati et al. 15 assessed the same for Musa cultivars in Rwanda and found a lower diversity index, which was prone to genetic erosion.Species evenness (E) is the measurement of the relative abundance of different species.The species evenness ranges from zero to one, with zero signifying no evenness and one signifying complete evenness.Shivamogga had more diverse landraces than other districts in terms of Evenness (E) with a value of 0.5 followed by Dakshina Kannada (E = 0.556), Uttara Kannada (E = 0.591) and Belagavi (E = 0.625) (Fig. 6).
The highest species richness (R) was observed in Shivamogga (40) followed by Uttara Kannada (29), Dakshina Kannada (18) and Belagavi (7) (Fig. 6).The current study revealed that Uttara Kannada and Shivamogga had more landrace diversity for their practice of sustenance farming in remote areas, use of landraces in local food systems, traditional and cultural links.While, Belagavi had less diversity in all the terms due to various probable reasons like commercialization of agriculture, use of more improved and hybrid varieties and, so on.

Socio-economic characteristics of custodian farmers
Among the 24 sites of on-farm conservation, three farmers possessed more than 10 ha farm land, 12 had medium sized farms (2-10 ha), whereas nine were found to have small farms (< 2 ha).Landraces of field crops (rice and pulses) along with vegetables and tuber crops were found conserved mainly on the small farms.On the other hand, perennial species including fruits, spices and plantation crops were in medium to large farms.Among the  www.nature.com/scientificreports/24 on-farm conservation sites, the age of the custodian farmers ranged from 35 to 75 years; majority (12) were in the age bracket of 40-60 years.The two young farmers (< 40 years) actively engaged in on-farm conservation were exclusively involved in commercially attractive activity of maintaining the rootstocks of traditional cultivars of perennial crops (pepper, mango and jackfruit) popular for their adaptation and resistance to pests and diseases 36 .However, it was starkly clear in our survey that younger generation of farmers is not inclined to engage in on-farm conservation.It was evident from the interaction with farmers that traditional knowledge accumulated over the years with the experienced farmers could be in danger of not finding next-generation custodians.
From the current study, it was also found that majority of farmers are conserving many landraces dedicated to few crops instead of single landrace covering entire farming area.Few farmers conserve rice landraces, by growing most of the landraces in a 10 m 2 area in order to maintain and preserve their self-interest and passion for conservation; and only a few landraces are grown in a large area because of their potential use.For example, Nereguruli Batta (rice) tolerates submergence condition up to 40 days in Shivamogga district.Fruits were grown majorly as an intercrop with spice and plantation crops.Some vegetables, fruits (mango and jackfruit) and miscellaneous crops were well-looked-after and maintained in home gardens for their use in preparing traditional dishes (mango-pickle, jackfruit-chips, idli) and traditional medicine.The marketing of the farm produce is distinct for different farmers based on the reason for cultivation.Many farmers grow landraces mainly for their personal use and are part of local food systems (pickling varieties of mango and vegetable landraces).Few landraces have cultural and traditional importance along with some quality traits that enjoy demand in local markets and weekly fairs (jackfruit varieties, local tuber crops).Very few landraces have demand in the countrywide market for their nutritional and medicinal importance (Navara and Ambe Mohar in rice).
Custodian farmers in the study area are majorly residing in remote villages and villages located in the vicinity of the forest.It was found that, the nearest proper road was 20-25 km away from the on-farm conservation sites.In the absence of market attraction, these farmers were found to cultivate landraces mainly for home consumption.At best, grains are sold at the local weekly bazaars and seeds are exchanged with fellow farmers and relatives.In exceptional cases, farmers who reside nearer to markets of nearby towns (< 10 km) were observed to get good prize for their produce.
Farmers generally designate local landraces names after specific characteristics.The appearance of seed and kernel, crop plants, taste, aroma, maturity, plant size, use and growing conditions are all crucial factors in determining a landrace name 33,37 .The same pattern of use/characteristics and other features are used to name traditional landraces/cultivars in the Central Western Ghats.It was observed that number of farmsteads having on-farm conservation activity was very less.Farmers belonging to post-green revolution era (born after 1970's), tend to cultivate high yielding modern varieties with a focus on enhanced income generation.In the absence of formal documentation, the only source of information about names of landraces and their specialty uses is the senior farmers belonging to age bracket of 60 and above.

Determinants of on-farm conservation
Farmers have indulged in selecting, growing and maintaining landrace biodiversity within and among the crops in their fields and community seed banks from generation to generation.Farmers were well aware of the benefits of local cultivars, which includes high market value 10 , adaptation to adverse weather conditions, good eating quality, lodging resistance, resistance to pests and diseases, low production costs, and a consistent yield 14 .Scientific investigations in rice provided some insights into the utility of the landraces in crop improvement programs 38,39 .The Central Western Ghats is a partial forest area and few farms under this study are located in the vicinity of the forest area (Joida, Sagara, Sirsi, and Thirthahalli).The region receives heavy rainfall during monsoon (June-September) and a good amount of groundwater facility enhances agriculture in the region.Agriculture practiced in the region is mainly rainfed with few exceptions.This has led farmers to follow organic farming with fewer inputs, which indirectly chooses the local traditional varieties for their adaptation to the local environment for generations 14 .
From the present survey, it was observed that one set of farmers conserved landraces on-farm with sound knowledge on importance of landrace and conservation (direct conservation), while another set of farmers conserved landraces for their food and other needs without any knowledge on importance of landrace and awareness of conservation (indirect conservation).Special mention for the Kunabi tribes from the Joida area of Uttara Kannada, for their cultivation of unique rice and tuber crops' landraces in marginal land, forest land and kitchen gardens for the sake of family sustenance and tradition without knowing the actual importance of these landraces in national plant genetic resources system.The distribution of tuber crop landraces in the area follows the ideal environment for their growth and development, such as soils, precipitation, elevations and drainage are in line with the results reported by Alwis et al. 10 in Sri Lanka.This shows that many farmers were not aware of the concept of biodiversity conservation and on-farm germplasm conservation.However, they have contributed to on-farm germplasm conservation without their theoretical knowledge and awareness of germplasm conservation.
Though the economic benefit is the major driver of conservation 12,40 , non-economic factors like prestige for being the owner of diversity 12 , exchange of specific landraces and their products with neighbors, relatives and family friends 22 are among the others which motivate farmers to engage in on-farm conservation.Landraces/ traditional folk varieties are also conserved because of their adaptability to agro-climatic conditions viz., higher rainfall in the western side of the Western Ghats (adaptation of rice landraces for rainfed condition (Kayime), Rabi season (Kutti Kayime) in Dakshina Kannada, low fertility of forest soils in Uttara Kannada (tuber crops in Joida) 18 and Shivamogga.Socio-economic conditions including fragmented land, limited availability of inputs, poor financial condition of farmers and tolerance to biotic and abiotic stresses (e.g., Anthara Saale for drought and weed tolerance in rice; Marabadane/Kudane for bacterial wilt resistance in brinjal) have motivated farmers to cultivate landraces.Similarly, unique biological traits such as-size in Mituga banana, colour 41 27 and Ibbudla (cucumber) for making juice; preparation of traditional meals viz., sweet dish, puffed rice, kaayi kadubu, subzi, patrode 18,42 also motivate farmers to conserve and promote conservation of landraces.Many of the landraces are associated with the traditions and cultural practices of the communities.As a result, ethnic traditional cultural practices and customs play an important role in the preservation of traditional variations and crop genetic diversity on farms.Hence, conserving traditions indirectly helps to conserve landraces 43 .These motivations are in line with the results of Gajanana et al. 19 in India and Alwis et al. 10 in Sri Lanka.The present study is coherent with the results regarding the determinants/factors highlighted by Sthapit et al. 13 .Considering the high level of diversity among custodian farmers and improving their ties with other members of the community can result in on-farm agro-biodiversity conservation in situ 13,19 .

Exchange of conserved material
The seed exchange takes place between individuals or families inside the community or between close communities 12 .Seed flow occurs through purchase of seeds from inside or beyond the community mainly in bio-diversity fairs and seed melas, as well as seed borrowing from relatives and fellow farmers.These exchanges and borrowings occur in the study region for a variable number of reasons, including-lack of seed of a particular variety or landraces in the market; a desire to replace poor-quality seeds from old lots and seasons which may have poor germination; an interest in growing better cultivars by seeing other farmers' fields; a desire to test a different landrace/folk variety in search of suitable landrace to replace the existing one for specific land suitability; and exchanging seeds of one landrace for the seeds of different landrace.From the interaction, it was observed that, seed exchange among the farming communities is in practice for several years, which in turn increases the diversity in the farmers' field and indirectly conserves the specific landrace.Normally, the custodian farmers have a practice of collecting and storing the seeds for the next growing season, contributing to the maintenance of the crop diversity.Custodian farmers are farmers (men and women) who actively maintain, adapt and promote agricultural biodiversity and related knowledge at farm and community levels over an extended period of time, and are recognized by community members for doing so 13 .Often, custodian farmers do not act alone, but rather are actively supported in their efforts by family or household members.These features of seed conservation and exchange were discussed by Conversa et al. 11 in vegetable landraces conservation in the Puglia region of Italy.Similar kind of exchange was also found in our study area, where a collective exchange happens during events such as local markets or traditional ceremonies where a group of farmers or communities from different parts of the state exchange seeds through purchase or barter system.Furthermore, certain farmers in the study area had a great knowledge on the importance of conservation of landraces and they played an integrated role in motivating/encouraging/involving other fellow farmers in conservation.While interacting with a custodian farmer from Belagavi, who maintains a large number of landraces, we found that he distributed two to five landraces to interested farmers with a motive to increase area under landrace cultivation and to help the fellow farmers to sustain during difficult times.Thus, custodian farmers play a significant role in the seed flow and they are the main source of seeds in the region.Few farmers from Shivamogga develop nursery for sale of landraces, mainly pepper, jackfruit and pickling varieties of mango 36 .Through germplasm movement, these farmers are developing a dynamic process of diversity on their farms 22 .Increased cultivation of landraces achieved through seed exchange within and between communities, diversity fairs, and public awareness of the importance of landraces improves their use and conservation 34 .

Total economic value
Landraces are an essential component of agro-biodiversity conservation due to their direct and indirect benefits to farmers.The farmers conserve landraces to improve the sustainability of food, fuel, medical care and for future.Farmers value the landraces based on the importance.Poudel and Johnsen 44 summarized the total economic value of crop landraces as inclusion of both use value (direct use value, ecological function value, and option use value) and non-use value (existence value and bequest value).Economic valuation of landrace diversity is essential to generate information and knowledge for resource allocation to identify least cost strategies to conserve landraces diversity 45 .Among several species of landraces conserved on-farm, 76.67% (46 species) landraces are conserved for both use and non-use values (Fig. 7).The landraces of the majority of the species (46) are conserved on-farm for either existence or/and bequest value in addition to direct use value, ecological function value and option value, highlights the farmers involvement in conservation of landraces for benefit of others in current and future generations.

Constraints for conservation
The custodian farmers are doing their best to maintain, manage and promote the local varieties and landraces through seed exchange.In addition, they are passing traditional knowledge about these cultivars and disseminating their importance among their fellow farmers within and outside their community 13 .Unfortunately, the genetic diversity of landraces is rapidly diminishing in various parts of the world for a variety of reasons.This fact has also been supported by Hammer and Teklu 46 citing the introduction of high yielding varieties (HYVs) leading to replacement of landraces/traditional folk varieties.
Conservation constraints are broadly divided into agro-ecological, socio-economic and technical aspects.Flooding, drought, rainfall during harvest, landslides, poor soil quality and abnormal weather are the main agro-ecological constraints.Whereas socio-economic constraints include inadequate input, lack of availability of seed material, poor yield, lack of marketing facilities, deterioration of culture and traditions, lack of awareness of conservation, adoption of HYVs, lack of interest among young people and their migration to urban areas, the non-multiplication of seeds by the family and poor knowledge transfer.Constraints of technical cultivation comprises of pest and disease infestation, labor scarcity, improper storage conditions and poor germination rate 14 .The Western Ghats encompass hilly area covered with forests that receive heavy rainfall deteriorating soil conditions, by erosion, flooding, submergence of fields, landslides that are common intimidations for cultivar conservation.Based on the information obtained from custodian farmers, the loss of many landraces over the years due to the frequent occurrence of natural calamities in the study area was highlighted.They also emphasized that, lack of prevalence with different farmers in many landraces, they are unable to protect those landraces.Socio-economic conditions make a huge impact on conservation and are the core threatening factors for the conservation of landraces.The practice of adoption of HYVs since the green revolution replaces several landraces, especially in Belagavi and Dakshina Kannada, due to the lack of seed availability and poor yield lead to decrease importance in production and maintenance, especially in rice.Lack of awareness is another major problem for local cultivar conservation, as only a handful of farmers are indulging in cultivar conservation in forest and hilly areas.An increase in desire for a luxurious life and other job opportunities with the inflow of money from natives residing in other cities, states, and countries; agriculture, which was formerly the main occupation of the people, has taken a backseat.In alignment with this, farms and fields in the survey area have been turned into residential plots and commercial (retail) buildings, abandoning cultivation and agriculture 47 .
Deterioration of culture and traditions in rural areas, poor knowledge transfer from elders, increasing technology in cultivation and commercialization of agriculture has led to reduced desire for conservation by young farmers and migration to urban areas 48 .There are no defined and proper market chains for landraces in the Western Ghats region, which also affects the cultivation.Alwis et al. 10 discussed the marketing problems for tubers crops

Figure 1 .
Figure 1.Map showing the survey area (a) India map highlighted with the survey state (b) Karnataka map with four survey districts (highlighted with different colours).

Figure 6 .
Figure 6.Diversity and distribution assessment of landraces using SDI = Shannon Diversity Index, SiDi = Gini-Simpson Index, E = Evenness.A = Abundance, R = Richness for four surveyed districts.

Figure 7 .
Figure 7.Total economic value of landraces of different species conserved on-farm by the farmers of Western Ghats.

Use Value Non-Use Value Direct use value Ecological Function value Option use value Existence value Bequest value Direct human use (consumptive or non- consumptive):Yield, Straw, Food, Medicinal use, Use in food tradition, Cultural use Disease & Pest resistance, Adaptability and Resistance to adverse conditions Future use of known & unknown benefits: Genes for new varieties, Need for cultivation on adverse or marginal land in future) Satisfaction of knowing that landraces exists Satisfaction of knowing that landraces are available to others in the current and future generation (intergenerational equity) Figure
2. The nature of total economic value of landraces.Vol:.(1234567890)Scientific Reports | (2024) 14:10712 | https://doi.org/10.1038/s41598-024-61428-1www.nature.com/scientificreports/

Table 1 .
Details of the surveyed districts in Central Western Ghats of Karnataka, India.

Table 2 .
Prevalence of landraces in the survey area.

Landraces Frequency of occurrence Number of sites Prevalence index
. It has a unique taste and virtually gets dissolved while cooking and is also less astringent and less bitter when compared to other varieties of brinjal, and has got GI tag in the Udupi region, and Marabadane/Kudane (bacterial wilt resistance/used grafting) are among other brinjal landraces.Landraces of okra conserved are Bahuvarshika Bende (perennial), Aane Kombu Bende (very long fruits), Sunkada Bende (fruit contain protective hairs) and Entugere Bende (8 ridged fruit, large size) (Table2).Cucumber is one of the important vegetables and many dual-purpose cucumber landraces are conserved.Aane Mottu/Hegge Southe (red pulp, pumpkin size, sweet taste), Aati Southe Tubers Tubers are important for food and nutrition security, as well as adaptation to climate change.Among the tuber crops, Kunabi Mudli (taro) (3ft long, big size, soft after boiling) is used in the preparation of patrode (a local dish).

Table 3 .
Utility of landraces in the Central Western Ghats of Karnataka, India.